4,648 research outputs found

    Spin dynamics of the ferromagnetic superconductor UGe2_{2}

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    Inelastic neutron scattering was used to study the low energy magnetic excitations of the ferromagnetic superconductor UGe2_{2}. The ferromagnetic fluctuations are of Ising nature with a non-conserved magnetization and have an intermediate behavior between localized and itinerant magnetism.Comment: European Conference on Neutron Scattering, Montpellier 2003 (to appear in Physica B

    The Individual in the Animal Kingdom

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    The groundbreaking first book by a major evolutionary biologist, published in 1912, that anticipated current thinking about organismal complexity. Julian Huxley's The Individual in the Animal Kingdom, published in 1912, is a concise and groundbreaking work that is almost entirely unknown today. In it, Huxley analyzes the evolutionary advances in life's organizational complexity, anticipating many of today's ideas about changes in individuality. Huxley's overarching system of concepts and his coherent logical principles were so far ahead of their time that they remain valid to this day. In part, this is because his explicitly Darwinian approach carefully distinguished between the integrated form and function of hierarchies within organisms and loosely defined, nonorganismal ecological communities. In The Individual in the Animal Kingdom, we meet a youthful Huxley who uses his commanding knowledge of natural history to develop a nonreductionist account of life's complexity that aligns with seminal early insights by Darwin, Wallace, Weismann, and Wheeler. As volume editors Richard Gawne and Jacobus Boomsma point out, this work disappeared into oblivion despite its relevance for contemporary research on organismal complexity and major evolutionary transitions. This MIT Press edition gives Huxley's book a second hearing, offering readers a unique vantage point on the discoveries of evolutionary biology past and present

    Do different subjective evaluation criteria reflect distinct constructs?

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    This is not the published version. Published version available from: http://journals.lww.com/jonmd/pages/default.asp

    A qualitative exploration of whether lesbian and bisexual women are 'protected' from sociocultural pressure to be thin

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    Heterosexual women in Western cultures are known to experience body image concerns, dieting and disordered eating as a result of intense social pressures to be thin. However, it is theorised that lesbian and bisexual women belong to a subculture that is ‘protective’ of such demands. Fifteen non-heterosexual women were interviewed about their experiences of social pressure. Thematic analysis of their accounts suggests that such theorising may be inaccurate, because these lesbian and bisexual women did not feel ‘protected’ from social pressures and experienced body dissatisfaction. While they might attempt to resist thin idealisation, resistance is not centred around their sexuality

    Theoretical Study on Coexistence of Ferromagnetism and Superconductivity

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    On the basis of a two-dimensional t-t' Hubbard model in ferromagnetic and paramagnetic states, the triplet superconducting mechanism is investigated by the third-order perturbation theory with respect to the on-site Coulomb interaction U. In general, the superconducting state is more stable in the paramagnetic state than in the ferromagnetic state. As a special case, the dominant ferromagnetic superconductivity is obtained by the electron-electron correlation between the electronlike majority and holelike minority bands. Furthermore, it is pointed out that in some cases the two bands play an essential role for the coexistence of superconductivity and ferromagnetism.Comment: 5 pages, 10 figure

    Lameness in UK dairy cows: a review of the current status

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    Lameness in dairy cattle has been reported as a concern for welfare and economic reasons for over 20 years. This concern has been expressed from across the industry and has prompted the launch of a number of initiatives to address the problem. This article reviews the current status of lameness in dairy cows in the UK, outlines the current understanding of the condition and its impacts on welfare and productivity, and highlights areas where evidence is still lacking

    Pressure dependence of the magnetization in the ferromagnetic superconductor UGe_2

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    The recent discovery that superconductivity occurs in several clean itinerant ferromagnets close to low temperature magnetic instabilities naturally invites an interpretation based on a proximity to quantum criticality. Here we report measurements of the pressure dependence of the low temperature magnetisation in one of these materials, UGe_2. Our results show that both of the magnetic transitions observed in this material as a function of pressure are first order transitions and do not therefore correspond to quantum critical points. Further we find that the known pressure dependence of the superconducting transition is not reflected in the pressure dependence of the static susceptibility. This demonstrates that the spectrum of excitations giving superconductivity is not that normally associated with a proximity to quantum criticality in weak itinerant ferromagnets. In contrast our data suggest that instead the pairing spectrum might be related to a sharp spike in the electronic density of states that also drives one of the magnetic transitions.Comment: to appear in Phys. Rev. Let

    Pressure-temperature phase diagram of ferromagnetic superconductors

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    The symmetry approach to the description of the (P,T) phase diagram of ferromagnet superconductors with triplet pairing is developed. Taking into account the recent experimental observations made on UCoGe it is considered the case of a crystal with orthorhombic structure and strong spin-orbital coupling. It is shown that formation of ferromagnet superconducting state from a superconducting state is inevitably accompanied by the first order type transition.Comment: 4 pages, 1 figur
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